A spokesperson for West Yorkshire said it had "significant concerns" about Sir Norman's conduct at the time of the 1998 Macpherson Inquiry, which examined police conduct while investigating Lawrence's murder in a racist attack in April 1993.

Bettison faced no retrospective action for his role in Hillsborough and the subsequent cover up having stepped down while facing a disciplinary investigation.

His separate referral to the IPCC follows a search for evidence across the police service of similar behaviour to that which attempted to discredit the Lawrence family when they were the target of covert surveillance as they sought justice for their son's killing.

Police and Crime Commissioner Mark Burns-Williamson said three documents which emerged in a "thorough" search requested by the force's current chief constable had called Sir Norman's behaviour into question. He said:

These documents raise significant concerns over the role of Sir Norman Bettison in commissioning a report to be prepared in the respect of a key witness appearing before the Macpherson Inquiry.

This may suggest an attempt to intervene in the course of a public inquiry and influence the manner in which the testimony of a witness, who was due to present evidence before it, was received.

PCC Burns-Williamson also called for the police treatment of Lawrence's family to be urgently reviewed by an independent body.

He said: "I am sure the Independent Police Complaints Commission will do the same for these separate issues of concern indicating possible corrupt practices in the later period around the Macpherson Inquiry."